1. Field of the Invention
The present invention relates to a swiveling joint for pump jack. More particularly, the present invention relates to a swiveling joint between the working beam and the horse head of a pump jack. The present invention further relates to improved access to the pump jack for maintenance, repair, and inspection of an oil or gas well.
2. Description of Related Art Including Information Disclosed Under 37 CFR 1.97 and 37 CFR 1.98
A reciprocating piston pump in an oil well mechanically lifts liquid out of the well, when the downhole pressure is not sufficient to push the liquid to reach the surface. Rotary motion of a motor is converted to the vertical piston stroke into the wellbore. The suction created by the piston action lifts the liquid from the downhole location. There are several terms used to refer to a reciprocating piston pump, due to the distinctive appearance of this equipment. Those terms include “nodding donkey”, “horsehead pump”, “sucker rod pump”, “thirsty bird”, and “rocking horse”. A “pump jack” or “pumping unit” is a device to provide reciprocating movement for the downhole rod pumping action. The term, “pump jack” will be used throughout the present application.
Pump jacks are well known, and the basis of this technology has been around for at least hundreds of years, originating in steam engines for boats. Basic components of the pump jack include the motor, crank, counterweight, post arm, walking beam or working beam, a horse head, a bridle, and a rod. The motor provides rotary motion, which is translated through the crank, counterweight, post, working beam, and horse head to create reciprocating vertical movement in the bridle mounted on the horse head and attached to the rod. Access to these components of the pump jack is important for maintenance, repair, and inspection of the well. The scale of the components is significant, requiring heavy lifting and special equipment for manipulating and rearranging. For example, the horse head is bulky and heavy. Disassembly of the horse head from the working beam requires heavy lifting equipment to insure safety of workers and avoidance of damage to the horse head.
Prior art solutions to access for maintenance, repair, and inspection have also sought to avoid the disassembly of the pump jack. A swiveling joint between the horse head and the working beam, and accessories attached to the horse head are known. Chinese Patent Application No. 101864930, issued to Liu et al. on Oct. 20, 2010, discloses a device for turning the horse head of a pump jack. There is a system of plates and shafts to control the rotation, and a worm gear powers the rotation from the underside of the working beam. U.S. Pat. No. 4,092,872, issued to McClure on Jun. 6, 1978, describes the older accessories for attachment to the horse head. The patent shows a safety device attached to the horse head to protect against injuries and damage when removing the horse head for maintenance.
Prior art references also disclose general swiveling joint structures, which are not specifically aimed for a pump jack in an oil field. U.S. Pat. No. 1,913,976, issued to Colman on Jun. 13, 1933, discloses the worm gear and geared cam used to open and close a gate. The mechanical elements of the horizontally mounted worm gear and the perpendicular relationship to the rotation of the geared cam are known. U.S. Pat. No. 3,006,201, issued to Ross on Oct. 31, 1961, describes a well pump means as a pump jack. The horse head application is shown, but the swivel action by a worm gear is placed on the other end of the working beam. Also, the swivel action is not related to the horse head. The elements to utilize the action of the worm gear are located in a different place for a different function.
It is an object of the present invention to provide a swivel joint for a pump jack.
It is another object of the present invention to provide a swivel joint for a pump jack between the working beam and the horse head.
It is another object of the present invention to provide a safer pump jack for maintenance, repair, and inspection.
It is another object of the present invention to provide a pump jack with improved access for oil or gas well maintenance, repair, and inspection.
It is still another object of the present invention to provide a swivel joint for a pump jack, wherein the horse head can swivel in both directions on both sides of the working beam.
It is still another object of the present invention to provide a swivel joint with a worm drive coordinated with a position of the horse head.
It is still another object of the present invention to provide a swivel joint system with lubrication.
It is still another object of the present invention to provide a swivel joint system with a pivot pin compatible with a lubricator.
These and other objectives and advantages of the present invention will become apparent from a reading of the attached specifications and appended claims.